The Digestive System- All You Need To Know

  • What is The Digestive System?
  • What is Digestion?
  • Why is Digestion important?
  • How does The Digestive System work?
  • What is the foods journey through The Digestive System?
  • Stage 1: The Mouth
  • Stage 2: The Pharynx and Oesophagus
  • Stage 3: The Colon, Rectum and Anus
  • What are the organs of the Digestive System?
  • Pancreas
  • Liver
  • Gall Bladder

  • What is The Digestive System?

    The digestive system carries out a vital role processing the food and drink we consume to fuel the body, and then it deals with the waste by-products.

    The digestive system is made up of the gastrointestinal tract—also called the GI tract or digestive tract—and the liver, pancreas, and gallbladder. The GI tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. The hollow organs that make up the GI tract are the mouth, oesophagus, stomach, small intestine, large intestine, and anus. The liver, pancreas, and gallbladder are the solid organs of the digestive system.

    The small intestine has three parts. The first part is called the duodenum. The jejunum is in the middle and the ileum is at the end. The large intestine includes the appendix, cecum, colon, and rectum. The appendix is a finger-shaped pouch attached to the cecum. The cecum is the first part of the large intestine. The colon is next. The rectum is the end of the large intestine.

    Bacteria in your GI tract, also called gut flora or microbiome, help with digestion. Parts of your nervous and circulatory systems also help. Working together, nerves, hormones, bacteria, blood, and the organs of your digestive system digest the foods and liquids you eat or drink each day.

    What is Digestion?

    Digestion is the complex process of turning the food you eat into the energy you need to survive and the nutrients you need for growth, repair and maintenance of body tissues. The digestion process also creates waste that has to be eliminated.

    The digestive tract (or gut) is a long twisting tube that starts at the mouth and ends at the anus. It is made up of a series of muscles in its wall that coordinate the movement of food and of other cells in its lining that produce enzymes and hormones to aid in the breakdown of food. Along the way are three other organs that are needed for digestion: the liver, the gall bladder and the pancreas.

    Why is Digestion important?

    Digestion is important because your body needs nutrients from food and drink to work properly and stay healthy. Proteins, fats, carbohydrates, vitamins , minerals , and water are nutrients. Your digestive system breaks nutrients into parts small enough for your body to absorb and use for energy, growth, and cell repair.

    • Proteins break into amino acids

    • Fats break into fatty acids and glycerol

    • Carbohydrates break into simple sugars

    digestion the digestive systemthe human digestive system

    How does The Digestive System work?

    Each part of your digestive system helps to move food and liquid through your GI tract, break food and liquid into smaller parts, or both. Once foods are broken into small enough parts, your body can absorb and move the nutrients to where they are needed. Your large intestine absorbs water, and the waste products of digestion become stool.

    What is the foods journey through The Digestive System?

    The digestive system plays an important role in the absorption of nutrients into the body.  It takes the food we ingest, breaks it down mechanically and chemically in the mouth and stomach.  It then absorbs nutrients, fats, proteins and water in the intestines before eliminating the waste through the rectum. 

    Stage 1: The Mouth

    The mouth is the beginning of the digestive system, and, in fact, digestion starts here before you even take the first bite of a meal. The smell of food triggers the salivary glands in your mouth to secrete saliva, causing your mouth to water. When you actually taste the food, the flow of saliva increases. Chewing begins the process of breaking the food down into pieces small enough to be digested, and saliva moistens the food to make it easier to swallow. It also contains enzymes that start to act on the food to break down or digest nutrients, turning the food into a form your body can absorb and use.

    Stage 2: The Pharynx and Oesophagus

    Also called the throat, the pharynx is the portion of the digestive system that receives the food from your mouth. Branching off the pharynx is the oesophagus that carries food to the stomach, and the trachea (windpipe) that carries air to the lungs. The act of swallowing takes place in the pharynx partly as a reflex and partly under voluntary control. The tongue and soft palate -- the soft part of the roof of the mouth -- push food into the pharynx, which closes off the trachea. The food then enters the oesophagus. The oesophagus is a muscular tube extending from the pharynx behind the trachea to the stomach. Food is pushed through the oesophagus and into the stomach by means of a series of muscular contractions called peristalsis. Just before the opening to the stomach is an important ring-shaped muscle called the lower oesophageal sphincter (LOS). This sphincter opens to let food pass into the stomach and closes to keep it there. If your LOS doesn't work properly, you may suffer from a condition called gastro-oesophageal reflux disease or GORD, also known as reflux, which causes heartburn and regurgitation (the feeling of food coming back up).

    Stage 3: The Colon, Rectum and Anus

    The colon (large intestine) is a one and a half to two metre (five to seven foot) long muscular tube that connects the small intestine to the rectum. It is made up of the ascending (right) colon, the transverse (across) colon, the descending (left) colon and the sigmoid colon, which connects to the rectum. The appendix is a small tube attached to the ascending colon. The large intestine is a highly specialised organ that is responsible for processing waste so that defaecation (excretion of waste) is easy and convenient. Stool, or faeces - the waste left over from the digestive process - passes through the colon by means of peristalsis, first in a liquid state and ultimately in solid form. As stool passes through the colon, most remaining water is absorbed. Stool is stored in the sigmoid (S-shaped) colon until a "mass movement" empties it into the rectum, usually once or twice a day. It normally takes about 36 hours for stool to get through the colon. The stool itself is mostly food debris and bacteria that normally live in the colon. These bacteria perform several useful functions, such as synthesising various vitamins, processing waste products and food particles, and protecting against harmful bacteria. When the descending colon becomes full of stool it empties its contents into the rectum to begin the process of elimination. The rectum is a 20 cm (eight inch) chamber that connects the colon to the anus. The rectum:

    • Receives stool from the colon.

    • Let’s the person know there is stool to be evacuated.

    • Holds the stool until evacuation happens.

    What are the organs of the Digestive System?

    There are a variety of essential organs for our body to function correctly and digest the correct foods into our body such as small intestines and large intestines mentioned above in the article. However, the three main organs of the digestive system include the pancreas, the liver and the gall bladder. 

    digestive system stageshuman digestive systemswallowing food digestion


    Among other functions, the pancreas is the chief factory for digestive enzymes that are secreted into the duodenum, the first segment of the small intestine. These enzymes break down protein, fats, and carbohydrates.


    The liver has multiple functions, but two of its main functions within the digestive system are to make and secrete an important substance called bile and to process the blood coming from the small intestine containing the nutrients just absorbed. The liver purifies this blood of many impurities before it travels to the rest of the body.

    Gall Bladder

    The gall bladder is a storage sac for excess bile. Bile made in the liver travels to the small intestine via the bile ducts. If the intestine doesn't need it, the bile travels into the gallbladder where it awaits the signal from the intestines that food is present. Bile serves two main purposes. First, it helps absorb fats in the diet and secondly, it carries waste from the liver that cannot go through the kidneys.